I'm 100% sure Metal Zone has been severely nerfed. I used to get about 7k exp for each normal kill, and a bit more for each the runners. The amount did not seem to change no matter which Metal Zone I did, whether it be 1, 2, or 3. Just nwo I did Metal Zone 1, and I was getting about 3500 exp for regular kills, and a bit more for runners. Didn't encounter a king.
This is fucking crazy. Was this announced anywhere? I have screenshots of pulling 200k on Metal Zone 1, and now I killed every enemy in the zone, nothing escaped, and I got about 65k. I've played alot of these type of f2p games, and I've never seen such a severe nerf. Really leaves a bad taste in my mouth right now.